Bull sharks, for some reason, gathered in large numbers. They were believed responsible for killing two surfers. A third surfer, Bruce Grimes, was more fortunate. The estimated nine-foot shark that raked his arm and hand (pictured, at right) after bumping his surfboard in an apparent attempt to knock him from it, did not pursue Grimes as he paddled toward shore.

The attacks, which occurred within a three-week period, generated "Jaws"-like mania and led to the erection of lifeguard towers and establishment of a shark patrol along a stretch of coastline that seasonally lures hundreds of surfers from Southern California and elsewhere.

Now it's May once more and some might be wondering whether the phenomenon will be repeated.

In the aftermath of last season's attacks I toured the beaches with Ed Kunze, a longtime resident and fishing guide. We also visited Majahua, a village of commercial fishermen, who keep close tabs on shark activity. They refused to dive last May but are currently combing the bottom for oysters, octopus and conch.

Ramon Caranza told Kunze this week that there "may not be" as many sharks in the area this season. More important, he said, there's an abundant supply of natural food, making sharks less dangerous to humans. Last May, Caranza said, natural food was scarce and whatever he caught in his nets was preyed upon by sharks. Caranza spoke as he repaired gaping holes in his home-fashioned monofilament nets.

George Burgess, a shark expert at the University of Florida, labeled Caranza's theory "an interesting mix of observation and speculation." Burgess said last year's congregation of sharks was probably the result of unusual oceanographic conditions. He also visited the region last year and noted that two of the surfers were attacked near river mouths, which are known to attract sharks during high runoff periods.

That runoff season is just getting underway. Surfers are riding waves and more surfers are expected over the coming weeks. There are bound to be shark sightings or alleged sightings. Already a small shark was reportedly seen in a wave face at Troncones, site of a fatal attack last May.

More than likely, last year's spate of attacks was a fluke and won't be repeated. But if you ask me, anyone surfing down there alone, near one of the river mouths, is asking for trouble.

--Pete Thomas

Photos: Bruce Grimes gives a thumb's up after surviving a shark attack last year at Playa Linda north of Ixtapa-Zihuatanejo on May 24. He required 50-plus stitches. In second photo, sign warns surfers to exercise caution. Credit: Pete Thomas/Los Angeles Times